Fully vaccinated people in the US can safely go without a face mask and not keep distance from others in most outdoor or indoor activities, new guidance from the Centres for Disease Control and Prevention says.
“We have all longed for this moment when we can get back to some sense of normalcy," CDC chief Dr Rochelle Walensky said on Thursday.
It was the largest easing of coronavirus prevention recommendations in the US.
"Anyone who is fully vaccinated can participate in indoor and outdoor activities, large or small, without wearing a mask or physical distancing," Dr Walensky said.
President Joe Biden remarked on the "historical" milestone in White House remarks following the CDC announcement.
"Today is a great day for America in our long battle with coronavirus," he said.
Fully vaccinated people are still required to wear a face mask if they are required under federal, state or local rules or laws, and in businesses or workplaces.
It remains unclear how quickly private spaces will introduce the new CDC guidance, given the difficulty of knowing whether people have been vaccinated.
Those who have are still required to wear masks on public transport, buses, trains or planes. The US transit authority still has a mask mandate enforceable through September 13 of this year.
Masks are also required in hospitals, correctional and detention centres and homeless shelters.
Dr Walensky said recent research confirmed fully vaccinated people did not suffer from severe illness or death from Covid-19 infection, and did not transmit the virus to others.
The US health agency says fully vaccinated people are those who have reached two weeks after their second of a two-dose vaccine or after a single-dose shot.
"If you are fully vaccinated, you can start doing the things that you had stopped doing because of the pandemic," Dr Walensky said.
The US has approved use of the two-dose vaccines by Moderna and Pfizer-BioNTech and the single-shot by Johnson & Johnson.
Everyone in the US is eligible to be vaccinated anywhere in its states and territories. Those 12 and over have just been approved to be inoculated with the Pfizer-BioNTech vaccine.
“The rule is very simple: Get vaccinated or wear a mask until you do,” Mr Biden said in his Thursday afternoon speech.
Big news from the CDC: If you’re fully vaccinated, you do not need to wear a mask – indoors or outdoors, in most settings.
— The White House (@WhiteHouse) May 13, 2021
We’ve gotten this far. Whether you choose to get vaccinated or wear a mask, please protect yourself until we get to the finish line. pic.twitter.com/XI4yPmhWaD
Mr Biden has set a goal to have 70 per cent of the US population receive at least one vaccine dose by July 4, the nation's independence holiday, and have the country reach a "closer to normal" environment.
More than 35 per cent of the US population have been fully vaccinated, along with 46.4 per cent who have had one dose, the CDC said.
More than 45 per cent of those aged at least 18 have been fully vaccinated, and 58 per cent have had at least one dose.
Mr Biden addressed remarks that some fully vaccinated people may choose to still wear a mask in light of the new guidance.
"Be patient with one another," he said. "You know, some may say, 'I just feel more comfortable continuing to wear a mask.' They may feel that way. So if you see them, please treat them with kindness and respect."
The country is experiencing its lowest number coronavirus cases since September with a seven-day moving average of more than 36,000 daily cases.
Deaths are also down, with an average of more than 580 a day.
More than 580,000 people have died with Covid-19 in the US, and more than 32 infections have been recorded, both more than any other country.
Recent research from the University of Washington suggests that more than 900,000 people have died with Covid-19 in the US, and the CDC is reviewing the report to see if the country's death toll should be increased as a result.
